Preparation of ketones

ABSTRACT

Ketones are prepared by treating secondary nitro-substituted compounds in the presence of a catalyst containing a metal of Group VIII of the Periodic Table at elevated temperatures and in a non-aqueous system. The invention is exemplified by the formation of acetone from 2-nitropropane.

United States Patent [1 Brennan 5] Mar. 27, 1973 PREPARATION OF KETONES[75] Inventor: John F. Brennan, Des Plaines, Ill.

[73] Assignee: Universal Oil Products Company,

- Des Plaines,lll.

[22] Filed: Feb. 20, 1970 [21] Appl. No.: 13,195

[52] US. Cl. ..260/593 R, 260/590, 260/591,

. 260/586 R [51] Int. Cl. ....C07c 49/06, C07c 49/08, C070 49/30 [58]Field of Search ..260/593 R, 590, 591, 586 R [5 6] References CitedUNITED STATES PATENTS 2,636,901 4/1953 I Tindall ..260/570.8 R

2,647,930 8/1953 Tindall ..260/590 Primary Examiner-Daniel D. HorwitzAttorneyJames R. Hoatson, Jr. and Raymond H. Nelson ABSTRACT 6 Claims,No Drawings PREPARATION OF KETONES This invention relates.to a processfor the preparation of keto compounds. More specifically, the inventionis concerned with the formation of ketones utilizing a secondary nitrocompound as the starting material. Oxygen-containing organic compounds,and particularly ketones, are important intermediates in the chemicalindustry. For example, one of the most common ketones, namely acetone,is used in the synthesis of acetic anhydride, diacetone alcohol, etc.,as a solvent in paints, lacquers and adhesives, in epoxy resins, fibers,pharmaceuticals, rubber antioxidants, etc. Another important ketone isbenzophenone or diphenyl ketone which is used in organic synthesis; inperfumery as floral odors and as a fixative, etc. while derivatives ofbenzophenone are used as ultraviolet absorbers. Likewise, cyclohexanoneis used in organic synthesis and particularly, in the preparation ofadipic acid and caprolactone; as a solvent for insecticides in aerosolbombs; as a solvent for basic dyes, fats, blown oils, waxes, cruderubber, resins and various other materials. It is also used in woodstains, paint and varnish removers, spot and stain removers, degreasingof metals, in polishes, as a leveling agent in dyeing and delustering ofsilk, etc. Ketones which are unsymmetrical in nature may also be formedaccording to this process, these ketones also being important chemicalcompounds. For example, methyl ethyl ketone is used in lacquers,dewaxing of lubricating oil, paint removers, cements and adhesives, incelluloid manufacture of smokeless powder, in artificial leatherdressings, dyes, cleaning fluids, printing, etc.

Heretofore, ketones have been formed from secondary nitro-substitutedcompounds in a Nef" process which consumes both caustic and acid, or bya slow, acid catalyzed hydrolysis. ln contradistinction to the prior artprocess, I have now discovered that it is possible to prepare ketonesfrom secondary nitro-substitutedcompounds by utilizing a metal of GroupVIII of the Periodic Table as a catalyst in a non-aqueous system, thecatalyst remaining in its natural state during the reaction and,therefore, being reusable in subsequent reactions. By utilizing such aprocess it is possible to prepare the ketones at a correspondingdecrease in expense and, therefore, the finished product will be lessexpensive to purchase.

It is therefore an object of this invention to provide a relativelyinexpensive process for the formation of ketones. I

A further object of this invention is to provide a process for thepreparation of ketones utilizing a catalytic composition of matter whichdoes not deteriorate or be consumed during the reaction and, therefore,is reusable for subsequent reactions.

In one aspect an embodiment of this invention resides in a process forthe preparation of a ketone which comprises treating a secondary nitrocompound at an elevated temperature in the presence of a catalyst.containing a metal of Group VIII of the Periodic Table,

and recovering the resultant ketone.

A'specific embodiment of this invention is found in a process for thepreparation of a ketone which comprises treating 2-nitropropane at atemperature in the range of from about 100 to about 250C. and a pressurein the range of from about atmospheric to about 100 atmospheres, in anon-aqueous medium in the presence of a catalyst comprising anickel-iron mixture, and recovering the resultant acetone.

Other objects and embodiments will be found in the following furtherdetailed description of the present invention.

As hereinbefore set forth the present invention is concerned with aprocess for the preparation of ketones by treating a secondarynitro-substituted compound in a non-aqueous medium at an elevatedtemperature in the presence of certain catalytic compositions of matterhereinafter set forth in greater detail. The secondary nitro-substitutedcompounds which may be utilized as the starting materials for theprocess of the present invention will possess the generic formula inwhich R is independently selected from the group consisting of alkyl,aryl, alkaryl, aralkyl, cycloalkyl radicals and methylene groups of fromtwo to six carbon atoms which together with the C form acyclic ring.Some specific examples of these compounds will include 2-nitropropane,Z-nitrobutane, Z-nitropentane, B-nitropentane, 2-nitrohexane,3-nitrohexane, 2-

nitroheptane, 3 -nitroheptane, 4-nitroheptane, 2- nitrooctane,3-nitrooctane, 4-nitrooctane, 2- nitrononane 3 -nitrononane,4-nitrononane 5 nitrononane, the isomeric 2-, 3-, 4-, 5-, etc..decanes,undecanes, dodecanes, tridecanes, tetradecanes, pentadecanes,hexadecanes, heptadecanes, octadecanes, nonadecanes, eicosenes, etc.both straight clia'in and branch chain in configuration; diphenylnitromethane, l,2-diphenyl-2-nitroethane, l,3-diphenyl-2- nitropropane,l,4-diphenyl-2-nitrobutane, 1,5-diphenyl-3-nitropentane, di-o-tolylnitromethane, di-m-tolyl nitromethane, di-p-tolyl nitromethane,dicyclopentyl nitromethane, dicyclohexyl nitromethane, l ,2-dicyclopentyl nitroethane, l,2-dicyclohexyl nitroethane, l ,3-dicyclopentyl-2-nitropropane 1 ,3

forded by the introduction of a gas, which is inert for' the particularreaction, into the reaction zone. Examples of these gases which areinert for this reaction include nitrogen, helium, carbon monoxide, etc.The reaction is effected in a non-aqueous medium in the presence of acatalyst comprising a compound containa ing a metal of Group VIII of thePeriodic Table. These catalysts will include the metals per se, such asiron, nickel, cobaltand the noble metals including platinum, palladium,ruthenium, rhodium, osmium and iridium or mixtures, thereof such asiron-nickel, iron-cobalt, cobalt-nickel. In addition, it is alsocontemplated within the scope of this invention that the metals may becomposited on a solid support such as carbon or metal oxides includingalumina, silica or mixtures thereof such as alumina-silica which havebeen pretreated with an alkali metal or alkaline earth metal, a specificexample of this type of catalyst being platinum or palladium compositedon an alumina support which has been pretreated by the addition of alithium compound such as lithium nitrate and thereafter calcined onpalladium composited on carbon.

The process of this invention may be effected in any suitable manner andmay comprise either a batch or continuous type operation. For example,when a batch type operation is used, the quantity of the secondarynitro-substituted compound is placed in an appropriate apparatus whichwill-contain the catalyst containing a metal of Group VIII of thePeriodic Table. It is contemplated, due to the fact that the reaction iseffected in a non-aqueous medium, that the charge stock could be driedprior to being charged to the reactor, by any drying steps well known inthe art. In another embodiment of the invention, the charge stockcomprising the secondary nitro-substituted compound may be placed in aparticular apparatus which is made. up of a metal or mixtures of metalsof Group VIII of the Periodic Table, one particular commerciallyavailable metal being stainless steel, which comprises mainly a mixtureof nickel and iron. The apparatus, whether of metal or containing acatalytic amount of a metal of Group VIII of the Periodic Table, is thenheated to the predetermined operating temperature andmaintained thereatfora desired residence time which may range from 0.5 up to about 20, ormore hours in duration. Upon completion of the desired residence timethe apparatus is cooled to room temperature and the reaction mixture isrecovered. After being subjected to conventional means of separationwhich includes washing, extraction, drying, fractional distillationunder reduced pressure, etc., the desired compound comprising a ketoneis recovered.

It is also contemplated within the scope of this invention that theprocess may be effected in a continuous manner of operation. Whenutilizing this type of operation the charge stock which has beenpreviously subjected to the drying step is continuously charged to areaction vessel which is maintained at the proper operating conditionsof temperature and pressure. As in the batch type method of effectingthe process, the reactor may comprise a metal of Group VIII of thePeriodic Table, or mixtures thereof, whereby no additional catalyst isrequired. However, if the reactor comprises glass, quartz, or islinedwith some non-metallic material, the catalyst comprising a metal ofGroup VIII of the Periodic Table must be added thereto. If the catalystis added as a separate entity, the continuous type of operation whichmay be employed will include a fixedbed type of operation in which thecatalyst is disposed as a fixed bed in the reactor and the charge stockpasses through said reactor in either an upward or downward flow, amoving bed type of operation in which the catalyst bed and. the reactorpass through the reactor either concurrently or countercurrently to eachother or the slurry type of operation in which the catalyst is carriedinto the reactor as a slurry in the charge stock. After completion ofthe desired residence time the reactor effluent is-contin'uouslywithdrawn and subjected to conventional means of separation whereby theunreacted secondary nitro-substituted compounds are separated from theketone and recycled to form a portion of the feed stock, the ketonecompound being. recovered and removed to storage.

Examples of ketones which may be prepared according to the process ofthis invention will include acetone, methyl ethyl ketone, methyl propylketone, methyl butyl ketone, methyl amyl ketone, methyl hexyl ketone,diethyl ketone, ethylpropyl ketone, ethylbutyl ketone, dipropyl ketone,dibutyl ketone, etc., benzophenone, 1,3-diphenyl acetone, diethylketone, 1,3-dicyclohexyl acetone, cyclopentanone, cyclohexanone,cycloheptanone, etc. It is to be understood that the aforementionedketones are only representative of the class of compounds which may beprepared, and that the'present invention is not necessarily limitedthereto.

The following examples are given to illustrate the process of thepresent invention which, however, are

not intended to limit the generally broad scope of the present inventionin strict accordance therewith.

EXAMPLE 1 A rotating autoclave was dried by heating under a nitrogenatmosphere and thereafter venting the nitrogen from the hot autoclave.Following this 225 mmole of 2-nitropropane which had been previouslydried over molecular sieves was charged to the reactor. In addition cc.of benzene which had been dried over a high surface area sodium was usedas a solvent. The autoclave, which comprised a stainless steel vessel,was sealed and carbon monoxide pressed in until an initial pressure of100 atmospheres wasreached. The autoclave was heated to a temperature of190C. and maintained thereat for a period of 6 hours. At the end of thistime heating was discontinued and the autoclave allowed 'to returntoroom temperature. The liquid products which were obtained were analyzedby means of a Gas-Liquid Chromatograph, there being recovered mmoles ofacetone.

EXAMPLE II In this example 157 mmoles of nitrocyclohexane was charged toa rotating autoclave which had been dried by heating under'a nitrogenatmosphere and thereafter venting the nitrogen from the hot autoclave.Previously to charging the nitrocyclohexane, it was dried over molecularsieves. In addition, the autoclave contained a catalyst comprisingplatinum composited on carbon. The autoclave was sealed and carbonmonoxide pressed in until an initial pressure of 100 atmospheres wasreached. The autoclave was then heated to a temperature of C. andmaintained thereat for a period of 6 hours. At the end of this timeheating was discontinued, the excess pressure was discharged and theautoclave was opened. Analysis of the liquid product by l ,S-diphenylmeans of a Gas-Liquid Chromatograph verified the formation ofcyclohexanone.

EXAMPLE I EXAMPLE IV In this example 225 mmoles ofa charge comprising apreviously dried 2-nitrobutane is placed in a stainless steel rotatingautoclave. In addition, a solvent comprising 100 cc. of benzene which isalso previously dried by passage over a high surface area sodium isplaced in the autoclave. The autoclave is sealed and heated to atemperature of 190C. for a period of 6 hours. At the end of this timeheatingis discontinued and the autoclave is allowed to return to roomtemperature. The liquid product is subjected to analysis by means of aGasethyl ketone is verified thereby.

EXAMPLE V Liquid Chromatograph and the presence of methyl' presence ofbenzophenone is verified thereby.

EXAMPLE VI To a stainless steel autoclave is added 200 mmoles of3-nitropentane and 100 cc. of benzene, the benzene is previously driedby passage over a high surface area sodium. In addition, prior tocharging the materials thereto, the autoclave is also dried by heatingunder a nitrogen atmosphere and thereafter venting said nitrogen whilethe autoclave is still hot. The autoclave is sealed and helium pressedin until an initial pressure of 10 atmospheres is reached. The autoclaveis heated to a temperature of 200C. and maintained thereat for a periodof 6 hours. At the end of this time heating is discontinued, theautoclave is allowed to return to room temperature and the excesspressure is vented. Recovery of the liquid product and analysis by meansof a Gas-Liquid Chromatograph will disclose the presence of diethylketone.

I claim as my invention:

1. A process for the preparation of a ketone which comprises reacting asecondary nitro-alkane in a nonaqueous medium and in contact with ametal of Group VIII of the Periodic Table at a temperature above 100C.to about 250C. and a pressure of from about atmos heric to about 100atmospheres. t I

2. e process as set forth in claim 1 in which said I secondary nitroalkane is 2-nitropropane and said To a glass tube containing a catalystcomprising palketone is acetone.

5. The process as set forth in claim 1 in which said secondary nitroalkane is 2-nitrobutane and said ketone is methyl ethyl ketone.

6. The process as set forth in claim 1 in which said secondary nitroalkane is 3-nitropentane and said ketone is diethyl ketone.

* III k

2. The process as set forth in claim 1 in which said metal is anickel-iron mixture.
 3. The process as set forth in claim 1 in whichsaid metal is palladium.
 4. The process as set forth in claim 1 in whichsaid secondary nitro alkane is 2-nitropropane and said ketone isacetone.
 5. The process as set forth in claim 1 in which said secondarynitro alkane is 2-nitrobutane and said ketone is methyl ethyl ketone. 6.The process as set forth in claim 1 in which said secondary nitro alkaneis 3-nitropentane and said ketone is diethyl ketone.